But when it came to waxing on the appropriate extent of the US national security apparatus, Snowden gave an answer that may surprise some.

"Not all spying is bad," he responded. "The biggest problem we face right now is the new technique of indiscriminate mass surveillance, where governments are seizing billions and billions and billions of innocents' communication every single day.

"This is done not because it's necessary ... but because new technologies make it easy and cheap."

People, Snowden noted, should be able to "dial a number, make a purchase, send an SMS, write an email, or visit a website without having to think about what it's going to look like on their permanent record."

Too sophisticated for mass surveillance

"This is a global problem, and America needs to take the lead in fixing it," Snowden continued. "If our government decides our Constitution's 4th Amendment prohibition against unreasonable seizures no longer applies simply because that's a more efficient means of snooping, we're setting a precedent that immunizes the government of every two-bit dictator to perform the same kind of indiscriminate, dragnet surveillance of entire populations that the NSA is doing."

He said it's because of this that he decided to act, even though those actions have led to felony charges in the US and forced him to seek temporary asylum in Russia.

The US intelligence community is well equipped to conduct targeted surveillance and shouldn't have to resort to mass surveillance, he argued.

"When we're sophisticated enough to be able to break into any device in the world we want to (up to and including Angela Merkel's phone, if reports are to be believed), there's no excuse to be wasting our time collecting the call records of grandmothers in Missouri," he concluded.